The attacks in the Indian Ocean port of Mocimboa da Praia, near the border with Tanzania and offshore gas fields, took place last Thursday and police have since regained control of the town, the official AIM news agency said.

The motive for the attacks were not clear and the government has not blamed the opposition group Renamo, against which it fought a civil war for almost two decades that ended in 1992. Fighting has periodically erupted since but a ceasefire has been in place since earlier this year.

"We need to know who they are, what their motives are, and where they came from," Celmira da Silva, the governor of the northern Mozambican province of Cabo Delgado, told Radio Mozambique.

Local media have reported that the attack was carried out by Islamists but the government has not confirmed this. Mozambique has not been a focal point of Islamist militant activity.

Mozambique police were expected to hold a press briefing in the capital Maputo on Tuesday about the attacks.